HVACHVAC

2.02.0

2.0 HVAC

2.1.3 Air-Conditioning Standards

1.Cooling and De-humidifyingfor summer cooling, temperatures of 68 deg to 74 deg F and 50% relative humidity are a frequent design average.

2. Heating and Humidifyingfor winter cooling, temperatures of 70 deg to 75 deg F and relative humidity of 30% to 35% are found most satisfactory.

3. Air Motionair velocity should average 4.57 to 7.6 meters per min measured 36” above the floor.

4. Air Supplya. 5 cuft to 7-1/2 cuft of air per minute per person (5-71/2 cuft/min/pers). In rooms where smoking is not allowed

b.25 cuft to 40 cuft of air per minute per person allowed in rooms where smoking is permitted.

2.1 General

2.1.1 Definition of Air-Conditioning

the simultaneous control of the temperature, humidity, motion and purity of the air in a confined space.

2.1.2 Functions or Elements of Air-Conditioning 1. Cooling and de-humidifying of air2. Heating or humidifying of air3. Cleaning of air or filtration4. Circulation of air

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC3. Passing the air through coils containing the refrigerant itself; in this case the coils are called “direct expansion” coils

4. Passing the air through a combination of sprays and coils

2.1.4 Methods of Cooling and De-humidifying

1. Passing the air through a spray of cold water

2. Passing the air through coils containing cold water

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.2 Refrigeration Cycle

1. Freon* is a gas at normal temperature and pressure. It is first subjected to high pressure in a compressor which raises its boiling point and temperature.

2. At the same high pressure, the vapor is piped into condenser coils where it is cooled by water to a degree below its liquefaction point. It condenses into a liquid state and still under high pressure, passes to the evaporator.3. In the evaporator, the pressure is relieved by the suction stroke of the compressor. The boiling point of the liquid refrigerant drops and evaporation into a vapor takes place. The water which surrounds the evaporator coils gives up its heat in causing the vaporization at low pressure, thus reducing its temperature to the temperature of the refrigerant. The cold water can then be piped at this low temperature to any desired point and sprayed to cool the passing air. The refrigerant is sucked back into the compressor and the cycle recommences

*Freon - refrigerant used for cooling. Mechanical refrigeration is based upon the alternate liquefying and evaporating of a volatile liquid with a low boiling point usually Freon 12 (Dichlorodiflouromethane) or Freon 11 (Trichloromonoflouromethane) during which processes it respectively gives off and takes in heat. The desirable properties of Freon are: a) high heat of vaporization; b) moderate pressure change for low to high temperature range; c) non-toxic; d) incombustible; e) non-explosive; and f) non-corrosive.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.3 Types of Air-Conditioning Systems

1. Central Systems

All-Season Centralized Air Conditioning System consists of the following:a. A method of cooling, a refrigeration plant

b. A source of heating such as a boiler or furnace

c. An Air Handling Unit (AHU) equipped with filters, pre-heater, spray, cooling coils and re-heater

d. The air distributing equipment composed of ducts, fans and air outlets

e. The necessary manual or automatic controls

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC2. Split Type Air Conditioning System

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

ACCU

AHU

EVAPORATOR

COMP.

CONDENSER

FCU(FAN COILUNIT)

ACCU

(AIR CONDITIONING CONDENSING UNIT)

2.0 HVAC3. Window Type Air Conditioning System

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC2. Condensers

a) Air-cooled Condensersused in unit and packaged-type air-conditioners up to 3 tons refrigeration.

b) Water-cooled Condensers

Double-piped Condensers:

2.4 Air-Conditioning Equipment

2.4.1 The Refrigeration Plant

1. Compressors

a) Piston Type or Reciprocating Compressorsfor tonnages up to 100 tons

b) Centrifugal Compressorsthese are quieter, have fewer vibration problems, require less maintenance and with better operating control

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC3. Evaporators

a) Shell and Tube Heat Exchangersimilar in operation to the shell and tube condenser. The refrigerant is expanded into a shell enclosing the tube through which the water flows.

b) Direct Expansion Coils (coils containing the refrigerant itself)This may either be installed in the spray chamber so that the water sprayed into the air comes into contact with the cooling coils or the air itself comes into direct contact with the cooling coils, as in the window type unit

Evaporative Condenser:

Shell and Tube Condensers:

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.4.4 Air Cleaning Equipment

1. Filters

2.4.2 Cooling and De-humidifying Equipment

1. Water Sprays

2. Cooling Coils

2.4.3 Heating and Humidifying Equipment

1. Tempering Coilscontains steam and are used to heating the air ie., preheaters and reheaters.

2. Water Heatersused for heating the water which will be used in the spray chamber to add heat and humidity to the air

a) Dry Filtersconsist of wire frames enclosing felt, cotton or sponge through which the air is screened.

b) Viscous Filtersconsist of metal deflecting plates or screens coated with viscous oil.

c) Water Sprays

d) Eliminator Platesconsist of corrugated galvanized iron sheets placed 1-1/8” apart which deflect the air flow about 30 deg catching the wet dust on the surfaces

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.4.5 Air Distribution Equipment

1. Ductsare usually of galvanized sheet metal, or aluminum sheets, usually rectangular in section, depending on the aspect ratio*, although circular ducts are also used for high velocity systems.

*Aspect Ratio – the ratio of the long side to short side; not to exceed 5:1 although 4 or 3:1 is preferred.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC2. Fans

a) Centrifugal fans (radial fans)these are intended for moving air at comparatively high pressures and are commonly used in duct systems.

b) Propeller or axial fanscommonly used for wall exhausts

3. Air Outletsthese are made for two locations: wall and ceiling.

a) Wall outlets include the following:Vaned outletsPerforated grills

b) Ceiling outlets include the following types:PlaquesPerforated panelsPerforated ceilings

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC2. Actuating or Operating Devices

a) DampersThese control the flow of air and are in the form of louvers.

b) Control ValvesThese are valves with variable orifices which are moved by motors to present smaller or larger openings as directed by a thermostat.

c) RelaysThese are devices that use electrical energy to amplify or convert the power of a thermostat or other controllers so that the resultant force will be sufficient and adaptable to operate a valve or damper.

2.4.6 Control Equipment

1. Sensing Devices

a) Humidistator Hygrostat is a controller, sensitive to the amount of humidity in the air.

b) Thermostata controller which responds to changes in temperature.

c) Pressure Regulatorsare instruments sensitive to changes in pressure. They may control a single pressure or a differential between two pressures.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

TYPE OF SYSTEM

HEATING MEDIUM

HEATING DEVICE

METHOD OF AIR

HANDLING

METHOD OF DISTRIBUTION

1. Mechanical Warm Air Heating System

Air Furnace Ducts Registers

2. Steam Heating System

Steam Boiler Pipes Radiators

3. Hot Water Heating System

Water WaterHeater

Pipes Radiators

4. Radiant Panel Heating System

1. Water2. Air3. Electricity

Water HeaterFurnaceElec Heater

PipesDuctsWires

Ceiling or FloorCeilingCeiling

2.5 Heating Systems

2.5.1 Types of Heating Systems

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.5.2 Mechanical Warm Air Heating System

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.5.2 Steam Heating System

2. Vacuum System (Two-pipe Steam Heating System)

1. Air-Vent System (One-Pipe Gravity System)

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2. Two-Pipe Hot Water Heating System

1. One-Pipe Hot Water Heating System

2.5.4 Hot Water Heating System

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.5.5 Radiant Panel Heating System

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVACCapacity of Works, Project or PlantThe total horsepower of all engines, motors, turbines or other prime movers installed, whether in operation or not.

CompressorA mechanical device for the purpose of increasing the pressure upon the refrigerant.

CondenserA vessel or arrangement of pipes or tubing in which vaporized refrigerant is liquefied by the removal of heat.

Condemned Boiler or Unfired Pressure VesselA boiler or unfired pressure vessel that has been inspected by the Building Official and declared unsafe or disqualified and power stamped or marked designating its rejection.

2.6 Provisions in the NBC Concerning HVAC

2.6.1 Definitions

Accidental ContactAny inadvertent physical contact with power transmission equipment, prime movers, machines or machine parts which could result from slipping, falling, sliding, tripping or any other unplanned action or movement.

Air ConditioningThe process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the requirements of the conditioned space.

BoilerA closed vessel for heating water or for application of heat to generate steam or other vapor to be used externally or to itself.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVACExternal InspectionAn inspection made on boiler during operation.

GuardedShielded, fenced or otherwise protected by means of suitable enclosure guards, covers or standard railings, so as to preclude the possibility of accidental contact or dangerous approach to persons or objects.

Internal InspectionAn inspection made when a boiler is shut down, with hand holes, manholes, or other openings opened or removed to permit inspection of the interior.

Liquid ReceiverA vessel permanently connected to a system by inlet and outlet pipes for storage of a liquid refrigerant.

Locomotive BoilerA boiler mounted on a self-propelled track locomotive used to furnish motivating power for traveling on rails.

CraneMeans a machine for lifting or lowering a load and moving it horizontally, the hoisting mechanism being an integral part of the machine.

DuctA passageway made of sheet metal or other suitable material not necessarily leak tight, for conveying air or other gases at low pressure.

EnclosedMeans that the moving parts of a machine are so guarded that physical contact by any part of the human body is precluded or prevented. This does not however prohibit the use of hinged, sliding or otherwise removable doors or sections to permit inspection, lubrication or proper maintenance.

EvaporationThat part of the AC/refrigeration system in which liquid refrigerant is vaporized to produce refrigeration.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVACPoint of OperationThat part of a machine which performs an operation on the stock or material and/or that place or location where stock or material is fed to the machine. A machine may have more than one point of operation.

Portable BoilerAn internally fired boiler which is self-contained, primarily intended for temporary location.

Prime MoverAn engine or motor operated by steam, gas, air, electricity, liquid or gaseous fuels, liquids in motion or other forms of energy whose main function is to drive or operate, either directly of indirectly, other mechanical equipment.

Process MachineAn equipment designed and operated for a specific purpose.

Low Pressure Heating BoilerA boiler operated at pressures not exceeding 1.05 kgs/sqm with steam or water temperature not exceeding 250ºF.

MachineThe driven unit of an equipment.

Machine HouseAn enclosure for housing the hoisting mechanism and power plant.

Machine PartsAny or all moving parts of a machine.

Mechanical Works PlantIncludes steam plants, internal combustion engine plants, hydraulic power plants, pumping plants, refrigerating plants, air conditioning plants, mill shops, factories, foundries, shipyards, etc. containing any mechanical equipment, machinery or process, driven by steam, internal or external combustion fuel, electricity, gas, air, water, heat, chemicals or other prime movers.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.6.2 Boilers and Pressure Vessels

1. Location of Boilers:

a) Boilers may be located inside buildings provided that the boiler room is of reinforced concrete or masonry and that the boiler room shall not be used for any other purpose.

b) In case the main building is not made up of fire resistive materials, boilers shall be located outside the building at a distance of not less than 3.00 m from the outside wall of the main building and the building housing the boiler shall be made up of fire resistive materials.

c) No part of the boiler shall be closer than one meter from any wall.

d) Fire tube boilers shall be provided with sufficient room for removal/replacement of tubes either thru the front or rear.

RefrigerantA substance which produces a refrigerating effect by its absorption of heat while expanding or evaporating.

Ton of RefrigerationThe useful refrigerating effect equal to 12,000 BTU/hour; 200 BTU/min.

Unfired Pressure VesselA vessel in which pressure is obtained from an external source or from an indirect application of heat.

VentilationProcess of supplying or removing air by natural or mechanical means to or from any space.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC5. Two check valves shall be provided between any feed pump and the boiler in addition to the regular shut-off valve.

6. Where two or more boilers are connected in parallel, each steam outlet shall be provided with a non-return valve and a shut-off valve.

7. Boiler rooms shall have at least two separate exits.

8. In no case shall the maximum pressure of an old/existing boiler be increased to a greater pressure than would be allowed for a new boiler of same construction.

9. Each boiler shall have at least one safety valve. For boilers having more than 46 sqm pressure of water heating surface or a generating capacity exceeding 907 kg per hour, two (2) or more safety valves shall be required.

2. Smokestacks whether self supporting or guyed, shall be of sufficient capacity to handle fuel gases, shall be able to withstand a wind load of 175 km per hour and shall rise at least 5 m above the eaves of any building within a radius of 50 m.

3. Manufacturers/assemblers of boilers/pressure vessels/pressurized water heaters shall stamp each vessel on the front head or on any other suitable location with the name of the manufacturer, serial number, maximum allowable working pressure, heating surface in sqm and year of manufacture.

4. Boilers of more than 46 sqm heating surface shall each be provided with two means of feeding water, one steam driven and one electrically driven, one pump and one injector.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC13. Upon the completion of the installation, the Building Official shall conduct an inspection and test, after which a certificate of operation for a period not exceeding one year shall be issued upon payment of the required inspection fees.

14. The Building Official shall notify the owner in writing of the intended date of the annual inspection at least 15 days in advance. However, the owner may request a postponement in writing of said inspection and the Building Official shall fix a date for inspection agreeable to both, but not to exceed 30 days from the intended date.

15. The owner or user of a boiler shall prepare the same for inspection by cooling it down blanking off all connections to adjacent boilers, removing all soot and ashes from tubes, heads, shell, furnace and combustion chamber. The owner shall assist the Building Official by providing all labor and equipment required during said inspection.

10. Each boiler shall have a steam gauge, with a dial range of not less than 1-1/2 times and not more than twice the maximum allowable working pressure. It may be connected to the steam space or to the steam connection to the water column.

11. Whenever repairs/replacements are made on fittings or appliances, the work shall comply with the section on New Installation of the Philippine Mechanical Engineering Code.

12. After a permit has been granted to install a boiler/pressure vessel/pressurized water heater upon payment of the installation fees thereof, it shall be the duty of the Building Official to make periodic inspection of the installation to determine compliance with the approved plans and specifications.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC5. Where ducts pass thru walls, floors or partitions, the space around the duct shall be sealed with fire resistant material equivalent to that of the wall, floor or partition, to prevent the passage of flame or smoke.

6. When ducts or the outlets or inlets to them pass through fire walls, they shall be provided with automatic fire dampers on both sides of the fire wall through which they pass.

7. Fire doors and fire dampers shall be arranged to close automatically and remain tightly closed, upon the operation of a fusible link or other approved heat actuated device, located where readily affected by an abnormal rise of temperature in the duct.

2.6.3 Refrigeration and Air-Conditioning

1. The temperature and humidity of the air to be used for comfortable cooling shall be maintained at 68-74ºF effective temperature at an air movement from 4.57 to 7.60 MPM within the living zone.

2. Water from evaporators, condensers and other machinery shall be properly collected into a suitable water or drainage system.

3. Ducts shall be constructed entirely of non-combustible materials such as steel, iron, aluminum or other approved materials. Only fire retardant lining shall be used on the inside of ducts.

4. Access doors shall be provided at all automatic dampers, fire dampers, thermostats and other apparatus requiring service and inspection in the duct system.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC12. Refrigerant piping crossing a passageway in any building shall not be less than 2.3 m above the floor.

13. In a refrigerating system containing more than 9 kgs, stop valves shall be installed in inlets and outlets of compressors, outlets of liquid receivers, and in liquid and suction branch header.

14. Window type ACs shall be provided with drain pipe or plastic tubing for discharging condensate water into a suitable container.

15. Window type AC installed on ground floors of buildings shall not be less than 2.13 m from the ground.

16. Window type ACs shall be provided with exhaust ducts if the exhaust is discharged into corridors/hallways/arcades/sidewalks etc.

17. Window type ACs installed along corridors/hallways/above the first floor shall not be less than 2.13 m above the floor level.

8. Each refrigerating system shall be provided with a legible metal sign permanently attached and easily accessible, indicating thereon the name of manufacturer or installer, kind and total number of kgs of refrigerant contained in the system and field test pressure applied.

9. In refrigerating plants of more than 45 kg refrigerant, masks and helmets shall be used. These shall be kept in a suitable cabinet outside the machine room when not in use.

10. Not more than 136 kgs of refrigerant in approved containers shall be stored in a machine room at any given time.

11. Where ammonia is used, the discharge may be into a tank of water, which shall be used for no other purpose except ammonia absorption. At least one gallon of water shall be provided for every 0.4536 kg of ammonia in the system.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC7. Piping carrying steam, hot water of hot liquids shall not be embedded in concrete walls or floors and shall be properly insulated to prevent accidental scalding to persons and to minimize heat loss.

8. Color coding of piping shall be as follows:

a) Steam DivisionHigh Pressure- WhiteExhaust System – Buff

b) Water DivisionFresh water, low pressure – Blue Fresh water, high pressure – Blue Salt water piping – Green

c) Oil DivisionDelivery – Brass or Bronze

Discharge – Yellowd) Pneumatic Division

All piping – Graye) Gas Division

All piping – Blackf) Fuel Oil Division

All piping – Blackg) Refrigerating Division

Pipes – BlackFittings – Black

2.6.4 Piping

1. Piping shall, as much as possible, run parallel to building walls.

2. Grouped piping shall be supported on racks, on either horizontal or vertical planes.

3. Piping on racks shall have sufficient space for pipe or chain wrenches so that any single line can be altered/repaired/replaced without disturbing the rest.

4. Piping 100mm in diameter and above shall be flanged. Smaller sized pipes may be screwed.

5. Piping subjected to varying temperatures shall be provided with expansion joints.

6. Galvanized piping shall not be used for steam.

2.1 General

2.2 Refrigeration Cycle

2.3 Types of Air-Conditioning Systems

2.4 Air-Conditioning Equipment

2.5 Heating Systems

2.6 Provisions in the NBC Concerning HVAC

2.0 HVAC

2.0 HVAC

2.0 HVAC

2.0 HVAC

refrigeration

END

HEATING, VENTILATION AND AIR-CONDITIONING